Recently, a two-piece solid golf ball or a three-piece solid golf ball comprising a cover and a solid core of one or two layers has been particularly popular with average golfers because of its large flying distance.
In the two-piece solid golf ball or three-piece solid golf ball, a high-rigid ionomer resin is normally used as a base resin of the cover so as to enhance impact resilience, thereby increasing flying distance.
However, the two-piece solid golf ball or three-piece solid golf ball using the high-rigid ionomer resin as the base resin of the cover has excellent characteristics that a flying distance is large, but has serious drawbacks as described in the following items (1) and (2).
(1) Since a slip is arisen on the face surface of the iron club at the time of shot, amount of spin largely varies and a flying distance is not stable. Particularly, drop ball, i.e. so-called flyer ball is liable to be arisen because of abnormal deterioration of spin at the time of iron shot from the rough. PA1 (2) Hard hit feeling is obtained at the time of hitting because of the material of the cover, and the hit feeling is inferior.
Therefore, in order to improve the above drawbacks, there have been developed a two-piece solid golf ball using a flexible cover material (see Japanese Kokai Publication Hei 1(1989)-308577).
In the two-piece solid golf ball using a flexible cover material, instability upon iron shot and hard hit feeling caused by the cover have already been solved. However, since a very hard core is used so as to make up for deterioration of impact resilience accompanied with the flexibility of the cover, excessive spin is put on the golf ball, which results in drastic decrease in flying distance. Further, the impact force increases because of hard core, Which results in deterioration of hit feeling.
As described above, a conventional two-piece solid golf ball or three-piece solid golf ball has such a drawback that a golf ball attaining a large flying distance is inferior in stability upon iron shot and hit feeling and, on the contrary, a golf ball having good stability upon iron shot and hit feeling attains a short flying distance. Therefore, there has been no golf ball which satisfies flying distance, stability upon iron shot and hit feeling, simultaneously.